1. Turn on the Galaxy S7 or Galaxy S7 Edge.
2. Go to the Home Screen and select on the Menu.
3. Select on Settings.
4. Select on Sound & Notifications.
5. Select on Other sounds.
6. Select on Call.
7. Select on Call Alerts.
8. Select on Call Signals.

After you follow the steps above, you’ll see an option to disable “Notification during calls” and all you need to do is uncheck the box to stop getting SMS text alerts while your on the phone.